Build Your Own Forecast of the 2026 Senate Elections

Thirty-five U.S. Senate seats are on the ballot in November 2026. This is an interactive tool for exploring what historical fundamentals imply under different scenarios — not a live forecast.

What you can do

Dial the national environment to set how far the cycle deviates from pure fundamentals (waves, surprise events, unpopular incumbents).
Add candidate-quality shocks in any state.
See the resulting map, seat totals, and win probability for each party's majority.

Model

Predicted margin for each state comes from a regression fit on historical Senate races, with a lagged state deviation term (Hummel & Rothschild 2015) that captures how the state's previous Senate race deviated from the national environment. Incumbent-averaging blends the model prediction with the state's last result adjusted for the previous cycle's environment and current presidential approval.

Related projects

By G. Elliott Morris, author of Strength In Numbers.